<!-- Licensed under a BSD license. See license.html for license -->
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes">
<title>WebGL - Textures - Wrap Modes</title>
<link type="text/css" href="resources/webgl-tutorials.css" rel="stylesheet" />
<style>
#ui {
    width: 380px;
    padding: 0.25em;
    font-size: small;
}
body, document {
    user-select: none;
    -webkit-user-select: none;
    -moz-user-select: none;
    -o-user-select: none;
    -ms-user-select: none;
}
#gridContainer {
    position: absolute;
    z-index: 2;
    top: 1px;
    left: 1px;
    width: 400px;
    height: 300px;
}
#gridContainer>svg {
    width: 100%;
    height: 100%;
}
#uiContainer {
    left: 15px;
    top: 15px;
}
#ui>div {
    margin-bottom: 1em;
}
#container {
  position: relative;
  /*
  not sure why but on mobile webkit the gridContainer
  is initially set to a large size after which
  it never shrinks because it's holding the page to at
  least that size. 

  This was one fix though not really understanding the original
  issue
  */
  width: 100vw;
  height: 100vh;
  overflow: hidden;
}
</style>
</head>
<body>
<div class="description">
Show texture wrapping modes<br/>
</div>
<div id="container">
  <canvas id="canvas"></canvas>
  <div id="gridContainer">
    <svg version="1.1"
        id="grid"
        viewBox="-50 -50 400 300"
        fill="none"
        stroke="none"
        xmlns="http://www.w3.org/2000/svg"
        xmlns:xlink="http://www.w3.org/1999/xlink">
      <g transform="matrix(1, 0, 0, 1, 0, 0)">
         <g stroke-width="0.25" stroke="#000000">
           <line x1="0"  y1="80" x2="0"  y2="85"/>
           <line x1="16" y1="80" x2="16" y2="85"/>
           <line x1="32" y1="80" x2="32" y2="85"/>
           <line x1="48" y1="80" x2="48" y2="85"/>
           <line x1="64" y1="80" x2="64" y2="85"/>
           <line x1="80" y1="80" x2="80" y2="85"/>

           <line y1="0"  x1="85" y2="0"  x2="80" />
           <line y1="16" x1="85" y2="16" x2="80" />
           <line y1="32" x1="85" y2="32" x2="80" />
           <line y1="48" x1="85" y2="48" x2="80" />
           <line y1="64" x1="85" y2="64" x2="80" />
           <line y1="80" x1="85" y2="80" x2="80" />
         </g>
         <g fill="#000000" font-size="5" font-family="monospace" text-anchor="middle">
           <text x="0"  y="90">-3</text>
           <text x="16" y="90">-2</text>
           <text x="32" y="90">-1</text>
           <text x="48" y="90">0</text>
           <text x="64" y="90">1</text>
           <text x="80" y="90">2</text>
           <text y="1"  x="90">4</text>
           <text y="17" x="90">3</text>
           <text y="33" x="90">2</text>
           <text y="49" x="90">1</text>
           <text y="65" x="90">0</text>
           <text y="81" x="90">-1</text>
         </g>
      </g>
    </svg>
  </div>
  <div id="uiContainer">
    <div id="ui">
      <div id="wrap_s">
        <div>TEXTURE_WRAP_S: </div>
        <div><input type="radio" id="wrap_s0" name="wrap_s" checked="true"/><label for="wrap_s0">REPEAT</label></div>
        <div><input type="radio" id="wrap_s1" name="wrap_s" /><label for="wrap_s1">CLAMP_TO_EDGE</label></div>
        <div><input type="radio" id="wrap_s2" name="wrap_s" /><label for="wrap_s2">MIRRORED_REPEAT</label></div>
      </div>
      <div id="wrap_t">
        <div><span>TEXTURE_WRAP_T: </span></div>
        <div><input type="radio" id="wrap_t0" name="wrap_t" checked="true"/><label for="wrap_t0">REPEAT</label></div>
        <div><input type="radio" id="wrap_t1" name="wrap_t" /><label for="wrap_t1">CLAMP_TO_EDGE</label></div>
        <div><input type="radio" id="wrap_t2" name="wrap_t" /><label for="wrap_t2">MIRRORED_REPEAT</label></div>
      </div>
    </div>
  </div>
</div>
</body>
<!-- vertex shader -->
<script id="vertex-shader-3d" type="x-shader/x-vertex">
attribute vec4 a_position;
attribute vec2 a_texcoord;

uniform mat4 u_matrix;

varying vec2 v_texcoord;

void main() {
  // Multiply the position by the matrix.
  gl_Position = u_matrix * a_position;

  // Pass the texcoord to the fragment shader.
  v_texcoord = a_texcoord;
}
</script>
<!-- fragment shader -->
<script id="fragment-shader-3d" type="x-shader/x-fragment">
precision mediump float;

// Passed in from the vertex shader.
varying vec2 v_texcoord;

// The texture.
uniform sampler2D u_texture;

void main() {
   gl_FragColor = texture2D(u_texture, v_texcoord);
}
</script>
<!--
for most samples webgl-utils only provides shader compiling/linking and
canvas resizing because why clutter the examples with code that's the same in every sample.
See https://webglfundamentals.org/webgl/lessons/webgl-boilerplate.html
and https://webglfundamentals.org/webgl/lessons/webgl-resizing-the-canvas.html
for webgl-utils, m3, m4, and webgl-lessons-ui.
-->
<script src="resources/webgl-utils.js"></script>
<script src="resources/m4.js"></script>
<script>
"use strict";

var zDepth = 50;

function main() {
  // Get A WebGL context
  var canvas = document.querySelector("#canvas");
  var gl = canvas.getContext("webgl", {antialias: false});
  if (!gl) {
    return;
  }

  // setup GLSL program
  var program = webglUtils.createProgramFromScripts(gl, ["vertex-shader-3d", "fragment-shader-3d"]);

  // look up where the vertex data needs to go.
  var positionLocation = gl.getAttribLocation(program, "a_position");
  var texcoordLocation = gl.getAttribLocation(program, "a_texcoord");

  // lookup uniforms
  var matrixLocation = gl.getUniformLocation(program, "u_matrix");
  var textureLocation = gl.getUniformLocation(program, "u_texture");

  // Create a buffer for positions
  var positionBuffer = gl.createBuffer();
  // Bind it to ARRAY_BUFFER (think of it as ARRAY_BUFFER = positionBuffer)
  gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);
  // Put the positions in the buffer
  setGeometry(gl);

  // provide texture coordinates for the rectangle.
  var texcoordBuffer = gl.createBuffer();
  gl.bindBuffer(gl.ARRAY_BUFFER, texcoordBuffer);
  // Set Texcoords.
  setTexcoords(gl);

  // Create a texture.
  var texture = gl.createTexture();
  gl.bindTexture(gl.TEXTURE_2D, texture);
  // Fill the texture with a 1x1 blue pixel.
  gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, 1, 1, 0, gl.RGBA, gl.UNSIGNED_BYTE,
                new Uint8Array([0, 0, 255, 255]));
  // Asynchronously load an image
  var image = new Image();
  image.src = "resources/f-texture.png";
  image.addEventListener('load', function() {
    // Now that the image has loaded make copy it to the texture.
    gl.bindTexture(gl.TEXTURE_2D, texture);
    gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA,gl.UNSIGNED_BYTE, image);

    // Check if the image is a power of 2 in both dimensions.
    if (isPowerOf2(image.width) && isPowerOf2(image.height)) {
       // Yes, it's a power of 2. Generate mips.
       gl.generateMipmap(gl.TEXTURE_2D);
    } else {
       // No, it's not a power of 2. Turn of mips and set wrapping to clamp to edge
       gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
       gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
       gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
    }
    drawScene();
  });

  var wrapS = gl.REPEAT;
  var wrapT = gl.REPEAT;

  document.querySelector("#wrap_s0").addEventListener('change', function() { wrapS = gl.REPEAT;          drawScene(); });  // eslint-disable-line
  document.querySelector("#wrap_s1").addEventListener('change', function() { wrapS = gl.CLAMP_TO_EDGE;   drawScene(); });  // eslint-disable-line
  document.querySelector("#wrap_s2").addEventListener('change', function() { wrapS = gl.MIRRORED_REPEAT; drawScene(); });  // eslint-disable-line
  document.querySelector("#wrap_t0").addEventListener('change', function() { wrapT = gl.REPEAT;          drawScene(); });  // eslint-disable-line
  document.querySelector("#wrap_t1").addEventListener('change', function() { wrapT = gl.CLAMP_TO_EDGE;   drawScene(); });  // eslint-disable-line
  document.querySelector("#wrap_t2").addEventListener('change', function() { wrapT = gl.MIRRORED_REPEAT; drawScene(); });  // eslint-disable-line

  function isPowerOf2(value) {
    return (value & (value - 1)) === 0;
  }

  function radToDeg(r) {
    return r * 180 / Math.PI;
  }

  function degToRad(d) {
    return d * Math.PI / 180;
  }

  var fieldOfViewRadians = degToRad(60);

  drawScene();

  window.addEventListener('resize', drawScene);

  // Draw the scene.
  function drawScene() {
    webglUtils.resizeCanvasToDisplaySize(gl.canvas);

    // Tell WebGL how to convert from clip space to pixels
    gl.viewport(0, 0, gl.canvas.width, gl.canvas.height);

    // Clear the framebuffer texture.
    gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

    gl.enable(gl.CULL_FACE);
    gl.enable(gl.DEPTH_TEST);

    // Compute the matrix
    var scaleFactor = 2.5;
    var tsize = 80 * scaleFactor;
    var x = gl.canvas.clientWidth / 2 - tsize / 2;
    var y = gl.canvas.clientHeight - tsize - 60;
    gridContainer.style.left = (x - 50 * scaleFactor) + 'px';
    gridContainer.style.top  = (y - 50 * scaleFactor) + 'px';
    gridContainer.style.width  = (scaleFactor * 400) + 'px';
    gridContainer.style.height = (scaleFactor * 300) + 'px';

    // Tell it to use our program (pair of shaders)
    gl.useProgram(program);

    // Turn on the position attribute
    gl.enableVertexAttribArray(positionLocation);

    // Bind the position buffer.
    gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);

    // Tell the position attribute how to get data out of positionBuffer (ARRAY_BUFFER)
    var size = 3;          // 3 components per iteration
    var type = gl.FLOAT;   // the data is 32bit floats
    var normalize = false; // don't normalize the data
    var stride = 0;        // 0 = move forward size * sizeof(type) each iteration to get the next position
    var offset = 0;        // start at the beginning of the buffer
    gl.vertexAttribPointer(
        positionLocation, size, type, normalize, stride, offset);

    // Turn on the texcoord attribute
    gl.enableVertexAttribArray(texcoordLocation);

    // bind the texcoord buffer.
    gl.bindBuffer(gl.ARRAY_BUFFER, texcoordBuffer);

    // Tell the texcoord attribute how to get data out of texcoordBuffer (ARRAY_BUFFER)
    var size = 2;          // 2 components per iteration
    var type = gl.FLOAT;   // the data is 32bit floats
    var normalize = false; // don't normalize the data
    var stride = 0;        // 0 = move forward size * sizeof(type) each iteration to get the next position
    var offset = 0;        // start at the beginning of the buffer
    gl.vertexAttribPointer(
        texcoordLocation, size, type, normalize, stride, offset);

    // Compute the projection matrix
    var projectionMatrix =
        m4.orthographic(0, gl.canvas.clientWidth, gl.canvas.clientHeight, 0, -1, 1);

    gl.bindTexture(gl.TEXTURE_2D, texture);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, wrapS);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, wrapT);

    var matrix = m4.translate(projectionMatrix, x, y, 0);
    matrix = m4.scale(matrix, tsize, tsize, 1);
    matrix = m4.translate(matrix, 0.5, 0.5, 0);

    // Set the matrix.
    gl.uniformMatrix4fv(matrixLocation, false, matrix);

    // Tell the shader to use texture unit 0 for u_texture
    gl.uniform1i(textureLocation, 0);

    // Draw the geometry.
    gl.drawArrays(gl.TRIANGLES, 0, 1 * 6);
  }
}

// Fill the buffer with the values that define a plane.
function setGeometry(gl) {
  var positions = new Float32Array(
    [
      -0.5,  0.5,  0.5,
       0.5,  0.5,  0.5,
      -0.5, -0.5,  0.5,
      -0.5, -0.5,  0.5,
       0.5,  0.5,  0.5,
       0.5, -0.5,  0.5,
    ]);
  gl.bufferData(gl.ARRAY_BUFFER, positions, gl.STATIC_DRAW);
}

// Fill the buffer with texture coordinates for a plane.
function setTexcoords(gl) {
  gl.bufferData(
      gl.ARRAY_BUFFER,
      new Float32Array(
        [
          -3, -1,
           2, -1,
          -3,  4,
          -3,  4,
           2, -1,
           2,  4,
        ]),
      gl.STATIC_DRAW);
}

main();
</script>
</html>



